Additional Study Information: People with mild cognitive impairment (MCI) are at increased risk of dementia, including Alzheimer's disease. Cognitive training may be a useful treatment strategy in MCI. The COGIT-2 study, which is funded by the National Institutes of Health, will compare the effects on cognition and function and brain MRI changes of high dose crosswords (4 puzzles per week), low dose crosswords (1 puzzle per week) and health education over an 18-month duration. The results will inform us about whether doing crosswords is useful, and how often they need to be done, in people with MCI.